Reaction of an aldehyde and unsaturated or acidic compounds in the presence of an initiator or catalyst is broadly old in the art with the type of product which results depending upon the particular chemical nature of the reactants and the type of catalyst or initiator which is employed. Ladd, U.S. Pat. No. 2,533,944, reacts certain propenyl compounds such as allyl acetate or diallyl ether with aldehydes such as formaldehyde or acetaldehyde to produce the corresponding keto- or formyl-substituted compound in the presence of free radical initiators such as peroxy compounds. The reaction products are largely one-to-one addition products of the aldehyde and the propenyl compound.
Ryu, U.S. Pat. No. 4,560,790, reacts saturated carboxylic acids or corresponding esters with formaldehyde to produce .alpha.,.beta.-unsaturated acids or derivatives, e.g., methacrylic acid or methacrylate esters. The process utilizes a specially produced acidic phosphorus-oxygen composition as catalyst. Here also, a one-to-one product results. Schneider, U.S. Pat. No. 4,165,438, describes a similar process using a vanadium orthophosphate catalyst. A related process is shown by Barlow, et al, U.S. Pat. No. 4,581,471, wherein the 1:1 condensation is conducted in the vapor phase in the presence of a high silica crystalline aluminosilicate zeolite catalyst.
While the above processes are useful in increasing the functionality of the unsaturated or acidic reactant through the formation of 1:1 addition products, it would be useful to provide a reaction of unsaturated carboxylic acid esters and aldeydes wherein the condensation is in a ratio of greater than 1:1 and thereby produce functionally substituted products of increased functionality.
In a related reaction, Japanese published patent application No. 57 88,149 (1982) and copending U.S. patent application Ser. No. 923,988, filed Oct. 28, 1986, (K-0625) describe the production of 4-oxoheptandioic acid or 4-oxoheptandioate esters by reaction of acrylate esters, carbon monoxide and hydrogen.